Predictive value of radiographic measurements as a diagnostic marker of systolic heart failure in a retrospective study: An old method, a new approach

Abstract

Background: A number of earlier studies have attempted to establish the validity of various radiological parameters for the assessment of cardiac enlargement, but these were not fully quantitative as echocardiographic measurements. Objectives: In our study, we aimed to determine the diagnostic accuracy of certain radiological parameters including the cardiothoracic ratio (CTR), cardiac area (CA) and cardiac volume (CV), derived from posteroanterior (PA) and lateral chest X-rays (CXR) in patients with impaired left ventricular ejection fraction (LVEF) suffering from dyspnea by comparing them with echocardiographic measurements of left ventricular (LV) dimensions and LVEF. Patients and Methods: This retrospective study included 374 patients (258 females and 116 males) aged 35 to 78 years with the complaint of dyspnea. CXR and echocardiographic examination were performed on each patient upon admission. Based on LVEF, the patients were divided into two groups: Group 1 consisted of patients with impaired LVEF (< 50%) and group 2 consisted of patients with normal LVEF (? 50%). The sensitivity, specificity, and cut-off points were evaluated by both receiver-operator characteristic (ROC) analyses and area under the ROC curve (AUC) to determine the diagnostic accuracy of CA, CV, and CTR. Results: Therewasnosignificant relationship betweenCTRandLVEF, butCAandCVshoweda strong correlation with LVEF (P< 0.001 and P < 0.00001, respectively). LV dimensions correlated better with CV than with CA (P < 0.00001 and P < 0.0001, respectively). According to the analysis of ROC curves, the best cut-off value for CV for the diagnosis of systolic heart failure was 825 mL. Conclusion: The CV value correlated more closely with low LVEF and more accurately indicated an enlarged heart than CA or CTR. This may be due to the fact that an anteroposterior measurement of heart size is included in the former but not the latter two measurements. These study results may help quantify left heart enlargement with greater accuracy than may be obtained from standard CXR. © 2016, Tehran University of Medical Sciences and Iranian Society of Radiology.